U.S. patent number 10,808,593 [Application Number 15/937,625] was granted by the patent office on 2020-10-20 for exhaust gas treatment for an internal combustion engine.
This patent grant is currently assigned to Vitesco Technologies GmbH. The grantee listed for this patent is Continental Automotive GmbH. Invention is credited to Hao Chen, Michael Nienhoff, Paul Rodatz, Hong Zhang.
United States Patent |
10,808,593 |
Nienhoff , et al. |
October 20, 2020 |
Exhaust gas treatment for an internal combustion engine
Abstract
An internal combustion engine makes available exhaust gas which
can be treated by means of a catalytic converter and a particle
filter. A method for determining the particle load of the particle
filter comprises steps of determining the storage capacity of the
catalytic converter for oxygen and determining the particle load of
the particle filter on the basis of the determined storage capacity
in the controller.
Inventors: |
Nienhoff; Michael (Regensburg,
DE), Rodatz; Paul (Landshut, DE), Zhang;
Hong (Tegernheim, DE), Chen; Hao (Regensburg,
DE) |
Applicant: |
Name |
City |
State |
Country |
Type |
Continental Automotive GmbH |
Hannover |
N/A |
DE |
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Assignee: |
Vitesco Technologies GmbH
(Hannover, DE)
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Family
ID: |
1000005130186 |
Appl.
No.: |
15/937,625 |
Filed: |
March 27, 2018 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20180216514 A1 |
Aug 2, 2018 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCT/EP2016/074180 |
Oct 10, 2016 |
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Foreign Application Priority Data
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Oct 13, 2015 [DE] |
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10 2015 219 777 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02D
41/1446 (20130101); F01N 3/035 (20130101); F02D
41/1454 (20130101); F02D 41/1441 (20130101); F02D
41/1445 (20130101); F01N 3/101 (20130101); F02D
41/0235 (20130101); F01N 9/002 (20130101); F02D
41/029 (20130101); F01N 2900/1411 (20130101); Y02T
10/40 (20130101); F01N 2560/025 (20130101); F01N
2900/1606 (20130101); F01N 2900/1624 (20130101); F01N
13/009 (20140601); F01N 2900/1404 (20130101); F02D
2200/0812 (20130101); F02D 2200/0816 (20130101); F01N
2560/14 (20130101); Y02T 10/12 (20130101); F01N
2560/06 (20130101) |
Current International
Class: |
F01N
9/00 (20060101); F01N 13/00 (20100101); F01N
3/035 (20060101); F02D 41/02 (20060101); F02D
41/14 (20060101); F01N 3/10 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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102654071 |
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Sep 2012 |
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CN |
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102009000410 |
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Jul 2010 |
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DE |
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102012202658 |
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Sep 2012 |
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DE |
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102011106933 |
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Jan 2013 |
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DE |
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102006025050 |
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Apr 2014 |
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DE |
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2956988 |
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Sep 2011 |
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FR |
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2004044457 |
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Feb 2004 |
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JP |
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4259361 |
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Apr 2009 |
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JP |
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Other References
JP 2004044457, Machine Translation, Translated on Dec. 3, 2019.
cited by examiner .
International Search Report and Written Opinion dated Jan. 5, 2017
from corresponding International Patent Application No.
PCT/EP2016/074180. cited by applicant .
Office Action dated May 31, 2016 from corresponding German Patent
Application No. 10 2015 219 777.8. cited by applicant .
Chinese Office Action dated Aug. 2, 2019 for corresponding Patent
Application No. 201680060135.4. cited by applicant .
Korean Office Action dated Jun. 27, 2019 for counterpart Korean
patent application 10-2018-7013369. cited by applicant .
Korean Notice of Decision Rejection, dated Dec. 18, 2019, for
counterpart Korean patent application 10-2018-7013369. cited by
applicant.
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Primary Examiner: Tran; Binh Q
Claims
The invention claimed is:
1. A method for a particle filter for an exhaust gas of an internal
combustion engine with a catalytic converter, the method
comprising: determining a storage capacity of the catalytic
converter for oxygen; and determining the particle load of the
particle filter on the basis of the determined storage capacity,
wherein the determination of the storage capacity of the catalytic
converter for oxygen comprises: operating, in a first phase, the
internal combustion engine with excess fuel relative to an amount
of oxygen in order to reduce oxygen stored in the catalytic
converter; following operating in the first phase, operating, in a
second phase, the internal combustion engine with excess oxygen
relative to an amount of fuel in order to permit the storage of
oxygen in the catalytic converter; sensing oxygen contents of the
exhaust gas upstream and downstream of the catalytic converter
during the second phase; and determining the storage capacity on
the basis of the oxygen contents of the exhaust gas sensed upstream
and downstream of the catalytic converter during the second
phase.
2. The method of claim 1, wherein the internal combustion engine is
a spark ignition engine.
3. A control device for a particle filter for an exhaust gas of an
internal combustion engine with a catalytic converter, wherein the
control device comprises: a processing device for determining the
particle load of the particle filter on the basis of the storage
capacity of the catalytic converter for oxygen; wherein the
processing device is configured to bring about regeneration of the
particle filter if the determined particle load exceeds a
predetermined threshold value, wherein the processing device is
configured to determine the storage capacity of the catalytic
converter for oxygen by operating, in a first phase, the internal
combustion engine with excess fuel in order to reduce, if
appropriate, oxygen stored in the catalytic converter; following
operating in the first phase, operating, in a second phase, the
internal combustion engine with excess oxygen in order to permit
the storage of oxygen in the catalytic converter; sensing oxygen
contents of the exhaust gas upstream and downstream of the
catalytic converter during the second phase; and determining the
storage capacity on the basis of the oxygen contents of the exhaust
gas upstream and downstream of the catalytic converter during the
second phase.
4. The control device of claim 3, wherein the regeneration
comprises actuating the internal combustion engine in order to
raise a temperature of the exhaust gas and to operate the internal
combustion engine with excess oxygen.
5. A system for controlling an internal combustion engine, the
system comprising: a particle filter and a catalytic converter for
exhaust gas of the internal combustion engine; a first oxygen
sensor for determining the oxygen content of the exhaust gas
upstream of the catalytic converter; a second oxygen sensor for
determining the oxygen content of the exhaust gas downstream of the
catalytic converter; a first control device having a processing
device configured to control combustion air ratio of the internal
combustion engine as a function of one of the determined oxygen
contents; and a second control device having a processing device
configured to determine a particle load of the particle filter
based upon a storage capacity of the catalytic converter, and to
bring about regeneration of the particle filter if the determined
particle load exceeds a predetermined threshold value, wherein the
second control device is configured to determine the storage
capacity of the catalytic converter for oxygen by operating, in a
first phase, the internal combustion engine with excess fuel in
order to reduce, if appropriate, oxygen stored in the catalytic
converter; subsequent to operating in the first phase, operating,
in a second phase, the internal combustion engine with excess
oxygen in order to permit the storage of oxygen in the catalytic
converter; and determining the storage capacity on the basis of the
oxygen contents of the exhaust gas upstream and downstream of the
catalytic converter during the second phase.
6. The system as claimed in claim 5, wherein the catalytic
converter and the particle filter are embodied integrated with one
another.
7. The method as claimed in claim 1, further comprising bringing
about regeneration of the particle filter if the determined
particle load exceeds a predetermined threshold value.
8. The method as claimed in claim 7, wherein regeneration of the
particle filter comprises actuating the internal combustion engine
in order to raise the temperature of the exhaust gas and to operate
the internal combustion engine with excess oxygen.
9. The method as claimed in claim 1, wherein the particle load is
determined based on a temperature of the exhaust gas.
10. The method as claimed in claim 1, further comprising receiving
a sensed oxygen content of the exhaust gas upstream of the
catalytic converter, receiving a sensed oxygen content of the
exhaust gas downstream of the catalytic converter, and controlling
a combustion air ratio of the internal combustion engine as a
function of one of the sensed oxygen content.
11. The method as claimed in claim 1, wherein the particle load is
determined based upon a space velocity of the exhaust gas.
12. The control device as claimed in claim 3, wherein the
processing device is configured to determine the particle load of
the particle filter based upon a temperature of the exhaust
gas.
13. The control device as claimed in claim 3, wherein the
processing device is configured to determine the particle load of
the particle filter based upon a space velocity of the exhaust
gas.
14. The control device as claimed in claim 3, wherein the
processing device receives a sensed oxygen content of the exhaust
gas upstream of the catalytic converter and a sensed oxygen content
of the exhaust gas downstream of the catalytic converter, and
controls a combustion air ratio of the internal combustion engine
as a function of one of the sensed oxygen content.
15. The system as claimed in claim 5, wherein regeneration of the
particle filter comprises actuating the internal combustion engine
in order to raise a temperature of the exhaust gas and to operate
the internal combustion engine with excess oxygen.
16. The system as claimed in claim 5, wherein the second control
device is configured to determine the particle load of the particle
filter based upon a temperature of the exhaust gas.
17. The system as claimed in claim 5, wherein the second control
device is configured to determine the particle load of the particle
filter based upon a space velocity of the exhaust gas.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of PCT Application
PCT/EP2016/074180, filed Oct. 10, 2016, which claims priority to
German Patent Application 10 2015 219 777.8, filed Oct. 13,
2015.
FIELD OF THE INVENTION
The invention relates to the exhaust gas treatment of an internal
combustion engine. In particular, the invention relates to a
particle filter in the exhaust gas stream of the internal
combustion engine.
BACKGROUND OF THE INVENTION
An internal combustion engine, in particular a reciprocating piston
engine, which is configured, for example, to drive a motor vehicle,
burns a mixture of fuel and oxygen. In this context, an exhaust gas
is produced which is treated in a catalytic converter in order to
reduce emitted pollutants. In order to be able to operate the
catalytic converter efficiently, the oxygen content of the exhaust
gas is determined and the internal combustion engine is controlled
in such way that a predetermined combustion air ratio (lambda,
.lamda.) is set. In order to purify the exhaust gas even further, a
particle filter can additionally be provided which is configured to
absorb particles in exhaust gas, mainly soot. Under predetermined
conditions, which can comprise, in particular, an increased
temperature of the exhaust gas or a specific quantity of remaining
residual oxygen in the exhaust gas, the particle filter
regenerates, wherein the particles are burnt.
If the internal combustion engine is used, for example, only in the
short-term operating mode, the necessary conditions do not occur
automatically and regeneration of the particle filter has to be
brought about actively by changing the operating point of the
internal combustion engine. If the excitation to regeneration fails
to occur, when there is a high soot load a spontaneous regeneration
can occur during which excessively high temperatures and high
temperature gradients can come about in the particle filter. These
can melt the filter material or give rise to high mechanical
stresses in the filter material. Both effects can damage the filter
irreversibly.
SUMMARY OF THE INVENTION
In order to actuate the regeneration of the particle filter, its
load with particles is usually determined on the basis of a model,
and regeneration is correspondingly brought about before the load
exceeds a predetermined value. The model can be determined, for
example, on the basis of an engine speed, an engine load or further
parameters. However, since the particle load of the particle filter
is not measured in this way but instead only tracked, the actual
conditions can deviate from the determined conditions. The actual
particle emissions of the internal combustion engine can change
over its service life or owing to a fault, with the result that a
significantly incorrect particle load can be determined.
The object of the present invention is to determine the particle
load of an individual particle filter in an improved way. The
invention achieves this object by means of the subjects of the
claims.
An internal combustion engine makes available exhaust gas which can
be treated by means of a catalytic converter and a particle filter.
A method for determining the particle load of the particle filter
comprises steps of determining the storage capacity of the
catalytic converter for oxygen and determining the particle load of
the particle filter on the basis of the determined storage
capacity.
It has been recognized that the particle load can be determined on
the basis of the oxygen storage capacity of the catalytic converter
and, if appropriate, of other parameters, for example the
temperature of the exhaust gas or its space velocity. The oxygen
storage capacity of the catalytic converter is usually determined
on a regular basis, for example before or during every driving
cycle. This may be necessary in order to diagnose a fault in the
region of the catalytic converter or the oxygen sensor (lambda
probe). The particle load of the particle filter can therefore be
determined with little expenditure and usually without using
additional sensors. The determined particle load relates to the
individual particle filter which is present, with the result that
influences of the aging of the internal combustion engine, of the
defect of one of its components, for example an injector, or
another fault do not influence the determination accuracy of the
method, or only do so to a small degree.
In particular, the method is suitable for use on a spark ignition
engine, since here the determination of the particle load on the
basis of a differential pressure is, in contrast with a diesel
engine, possible only with difficulty, or not at all, owing to the
low differential pressures.
In one embodiment, the oxygen storage capacity of the catalytic
converter comprises steps of operating, in a first phase, the
internal combustion engine with excess fuel in order to reduce, if
appropriate, oxygen stored in the catalytic converter, and of
operating, in a second phase, the internal combustion engine with
excess oxygen in order to permit the storage of oxygen in the
catalytic converter, and of determining the storage capacity on the
basis of the oxygen contents of the exhaust gas upstream and
downstream of the catalytic converter during the second phase. In
order to implement these method steps, a first lambda probe
upstream of the catalytic converter and a second downstream are
essentially sufficient. The determination of the oxygen storage
capacity can be carried out easily and quickly.
A computer program product comprises program code means for
carrying out the method described when the computer program product
runs on a processing device or is stored on a computer-readable
data carrier.
A control device for a particle filter for an exhaust gas of an
internal combustion engine with a catalytic converter comprises a
processing device for determining the particle load of the particle
filter on the basis of the storage capacity of the catalytic
converter for oxygen, wherein the processing device is configured
to bring about regeneration of the particle filter if the
determined particle load exceeds a predetermined threshold
value.
The processing device can comprise, in particular, a programmable
microcomputer which is preferably configured to carry out, for
example by means of the computer program product described above,
the method which is described further above. The regeneration of
the particle filter can be brought about by making available a
corresponding message to a control device for the internal
combustion engine. In a further embodiment, the control devices for
the particle filter and for the internal combustion engine are
integrated with one another, with the result that the regeneration
of the particle filter can be brought about or actuated
directly.
In order to carry out the regeneration of the particle filter, in
particular the internal combustion engine can be actuated in such a
way that the temperature of the exhaust gas is raised and/or the
internal combustion engine is operated with excess oxygen. For
this, for example a quantity of injected fuel can be influenced as
a function of an air mass which the internal combustion engine
takes in. In further embodiments, control times for an inlet valve
or outlet valve, an ignition time or another operating parameter of
the internal combustion engine can be changed in order to raise the
exhaust gas temperature and/or to ensure that the exhaust gas
comprises a predetermined quantity of oxygen.
A system for controlling an internal combustion engine comprises a
particle filter and a catalytic converter for exhaust gas of the
internal combustion engine, a first oxygen sensor (lambda probe)
for determining the oxygen content of exhaust gas upstream of the
catalytic converter, a second oxygen sensor (lambda probe) for
determining the oxygen content of the exhaust gas downstream of the
catalytic converter, a first control device for controlling the
combustion air ratio of the internal combustion engine as a
function of one of the determined oxygen contents, and a second
control device such as has been described above.
It is particularly preferred that the catalytic converter and the
particle filter are embodied integrated with one another. The
catalytic converter preferably comprises a three-way catalytic
converter, wherein the term four-way catalytic converter can also
be used in combination with the particle filter.
BRIEF DESCRIPTION OF THE FIGURES
The invention will now be described more precisely with reference
to the appended figures, in which:
FIG. 1 illustrates schematically a system for controlling an
internal combustion engine; and
FIG. 2 illustrates schematically a relationship between an oxygen
storage capacity of a catalytic converter and a particle load of a
particle filter of the system in FIG. 1.
DETAILED DESCRIPTION
FIG. 1 shows a system 100 for controlling an internal combustion
engine 105. The internal combustion engine 105 is preferably
configured to drive a motor vehicle and is more preferably embodied
as a spark ignition engine. A first control device 110 is
configured to control the internal combustion engine 105, in
particular an operating point of the internal combustion engine
105. For this purpose, it is possible to influence different
components of the internal combustion engine 105, for example an
injector 115 for injecting a predetermined quantity of fuel into a
combustion chamber 120, an ignition device 125 for igniting a
mixture of fuel and oxygen in the combustion chamber 120 at a
predetermined time, an inlet adjustment means 130 for influencing
an inlet time of air into the combustion chamber 120, an out
adjustment means 135 for influencing an outlet time of exhaust gas
from the combustion chamber 120 and, if appropriate, other
components also. The control can be carried out on the basis of
measured values at the internal combustion engine 105, for example
a rotational speed of an output shaft 140, a temperature of a
component of the internal combustion engine 105, or a mass of air
which is let into the internal combustion engine 105 or the
internal combustion engine 120.
During the combustion of fuel and oxygen, which is contained in the
air which has been let into the combustion chamber 120, an exhaust
gas 145 is produced which can be treated and, in particular,
purified, by means of the system 100. The system 100 comprises, in
particular, a catalytic converter 150, which is preferably embodied
as a three-way catalytic converter, and a particle filter 155 which
is embodied integrated with the catalytic converter 150 in the
illustrated embodiment. In other embodiments, the catalytic
converter 150 and the particle filter 155 can also be connected in
series, for example with respect to a direction of flow of the
exhaust gas 145. The system 100 also comprises a first oxygen
sensor 160 upstream of the catalytic converter 150, and a second
oxygen sensor 165 downstream of the catalytic converter 150.
Furthermore, a second control device 170 is provided which is
configured to determine a particle load of the particle filter 155.
The particles which have accumulated there are absorbed from the
stream of exhaust gas 145 from the internal combustion engine 105.
The second control device 170 is preferably connected to one or
more sensors and/or to the first control device 110 in such a way
that it is provided with a value for the oxygen storage capacity of
the catalytic converter 150 and preferably also for the temperature
of the exhaust gas 145 or the space velocity of the exhaust gas
145. The temperature can be detected by means of a dedicated
temperature sensor 175 which can be mounted at different locations
in the exhaust gas conduction system or can be obtained from the
first control device 110 which can determine the temperature on the
basis of the temperature sensor 175 or by means of the
determination on the basis of a model. The space velocity of the
flow of exhaust gas 145 is preferably also determined by the first
control device 110 and made available to the second control device
110.
The oxygen storage capacity of the catalytic converter 150 is
preferably determined in that in a first phase, the internal
combustion engine 105 is operated with excess fuel (.lamda.<1)
in order to reduce, if appropriate, oxygen stored in the catalytic
converter 150 and in a subsequent second phase, the internal
combustion engine 105 is operated with excess oxygen (.lamda.<1)
in order to permit the storage of oxygen in the catalytic converter
150, and the storage capacity of the catalytic converter 150 for
oxygen is determined on the basis of the oxygen contents of the
exhaust gas 145 upstream and downstream of the catalytic converter
150 during the second phase. These steps can alternatively be
carried out by the first control device 110 or the second control
device 170, for which purpose the oxygen sensors 160 and 165 are
correspondingly connected to the first control device 110 or the
second control device 170. It is also preferred that the first
control device 110 controls the operating state of the internal
combustion engine 105 as a function of at least one of the
quantities of oxygen determined by means of the oxygen sensors 160,
165.
The storage of particles from the stream of exhaust gas 145 through
the particle filter 155 is a function of the particle load of the
particle filter 155 and can additionally be dependent on the
temperature and/or on the space velocity of the stream of exhaust
gas 145. The second control device 170 is preferably configured to
determine the particle load of the particle filter 155 and to
compare it with a predetermined threshold value. If the determined
load exceeds the threshold value, regeneration of the particle
filter 145 can be brought about in that, in particular, the
operating point of the internal combustion engine 105 is changed in
such a way that the exhaust gas 145 has an increased temperature
and/or a predetermined quantity of residual oxygen is located in
the stream of exhaust gas 145. The execution of the regeneration
can alternatively be controlled by the first control device 110 or
the second control device 170. In a particularly preferred
embodiment, the control devices 110 and 170 are embodied integrated
with one another.
FIG. 2 shows a qualitative relationship between an oxygen storage
capacity of the catalytic converter 150 and a particle load of the
particle filter 155 of the system 100 in FIG. 1. A time profile is
plotted in the horizontal direction. An oxygen storage capacity 205
and a particle load 210 are plotted in the vertical direction, with
different ordinate axes. A first profile 215 is illustrated with an
interrupted line and relates to the oxygen storage capacity 205 of
the catalytic converter 150, and a second profile 220 is
illustrated with a dot-dashed line and relates to the profile of
the particle load 210 of the particle filter 155. For the sake of
better illustration, the profiles 215, 220 in FIG. 2 are plotted
offset vertically.
In a method 225, the oxygen storage capacity 205 of the catalytic
converter 150 is determined in a first step 230 at a time t1. In
addition, the temperature of the exhaust gas 145 and/or its space
velocity can also be determined. In a second step 235, the particle
load 210 of the particle filter 155 is determined by means of the
second control device 170 on the basis of the information acquired
in the first step 230. The determination can be carried out, for
example, by means of a characteristic diagram, wherein individual
values of the characteristic diagram have been determined in
advance experimentally or analytically. In another embodiment, the
particle load 210 is determined analytically on the basis of the
oxygen storage capacity 205 and, if appropriate, the temperature
and/or the space velocity of the stream of exhaust gas 145, for
example in that a predetermined, if appropriate multi-parameter,
function is used. The function can be specified, in particular, in
a polynomial fashion. Other embodiments for the determination of
the particle load 210 are also possible on the basis of the
specified parameters.
LIST OF REFERENCE SYMBOLS
100 System 105 Internal combustion engine 110 First control device
115 Injector 120 Combustion chamber 125 Ignition device 130 Inlet
adjustment means 135 Outlet adjustment means 140 Output shaft 150
Catalytic converter 155 Particle filter 160 First oxygen sensor 165
Second oxygen sensor 170 Second control device 175 Temperature
sensor 205 Oxygen storage capacity 210 Particle load 215 Profile of
the oxygen storage capacity 220 Profile of the particle load 225
Method 230 First step: Determining the oxygen storage capacity 235
Second step: Determining the particle load
* * * * *